Method of manufacturing a copper metal wiring in a semiconductor device

ABSTRACT

A method of manufacturing a copper metal wiring in a semiconductor device, by which a plasma process is performed before a diffusion barrier layer is formed and a chemical pre-process using a chemical enhancer is performed so that copper is deposited to form a metal wiring by a chemically enhanced chemical vapor deposition (CECVD) method. The method allows the chemical enhancer to be adhered on the diffusion barrier layer uniformly and stably; therefore, improving the deposition property of a copper thin film.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates generally to a method of manufacturing acopper metal wiring in a semiconductor device. More particularly, theinvention relates to a method of manufacturing a copper metal wiring ina semiconductor device capable of increasing absorption sites of achemical enhancer when copper is deposited to form a metal wiringthrough a chemically enhanced chemical vapor deposition (CECVD) method.

[0003] 2. Background of the Invention

[0004] As the performance of next-generation semiconductor deviceincreases, the size of a contact is reduced and the aspect ratioincreases. Therefore, when a metal wiring is formed, a good contactfilling property and a step coverage is required.

[0005] Presently, the manufacture of a metal wiring in a semiconductordevice uses a method by which, after a titanium thin film (Ti) isdeposited, aluminum (Al) is deposited thereon by a physical vapordeposition (PVD) method and a chemical vapor deposition (CVD) method, ortantalum (Ta) or tantalum nitride (TaN) thin film is formed as adiffusion prevention film by a PVD method and copper (Cu) is depositedby an electroplating method. This current methodology, however, has aproblem when applied to next-generation high-performance semiconductordevices since aluminum is higher in resistance than copper. In thelatter method, copper is limited in its filling property due to anabrupt reduction in the contact size and an increase in the aspectratio. Further, the tantalum nitride film used as a diffusion preventionfilm for copper must be very thin, which increases the resistancerelative to aluminum to which a diffusion prevention film is notapplied. Thus, applying the copper wiring to the next-generationsemiconductor device or using aluminum wiring and electroplating causesmany problems. In order to solve these problems, study of a method bywhich a CVD method is employed upon deposition of the copper wiring hasrecently been emphasized. However, due to a lower deposition speed, thismethod has a limit in bulk filling.

[0006] Recently, a method by which a copper thin film is deposited bymeans of a metal organic chemical vapor deposition (MOCVD) method usinga catalyst that includes iodine (I) has been studied. The MOCVD methodusing this catalyst is called a chemically enhanced chemical vapordeposition (CECVD) method. The chemical enhancer, e.g., iodine, heavilydepends on the surface property of a diffusion barrier layer. Further,if the chemical enhancer is directly deposited on the diffusion barrierlayer without deposition of a seed, the absorption property of thechemical enhancer is degraded. In other words, in case of an amorphouslayer or a dense thin film which does not provide a site on which thediffusion barrier layer can be deposited in a stable manner, thechemical enhancer will rarely adhere to the diffusion barrier layer andthe chemically enhanced effect will be diminished. Therefore, there is aproblem that a filling property of a copper metal wiring will bedegraded.

SUMMARY OF THE DISCLOSURE

[0007] A method of manufacturing a copper metal wiring in asemiconductor device is disclosed and comprises the steps of forming aninterlayer insulating film on a substrate in which an underlyingstructure is formed; forming a damascene pattern; performing a cleaningprocess; forming a diffusion barrier layer on the entire structure inwhich the damascene pattern is formed; performing a plasma process forthe entire structure in which the diffusion barrier layer is formed;performing a chemical pre-process using a chemical enhancer for thediffusion barrier layer for which the plasma process is performed;depositing copper on the entire structure so that the damascene patterncan be filled; and performing a chemical mechanical polish process sothat the damascene pattern can be filled, thus forming a copper metalwiring only within the damascene pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The aforementioned aspects and other features of the disclosedmethod will be explained in the following description, taken inconjunction with the accompanying drawings, wherein:

[0009]FIGS. 1A to 1E are cross-sectional views for explaining a methodof manufacturing a copper metal wiring in a semiconductor deviceaccording to one preferred embodiment.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0010] A method of manufacturing a copper metal wiring in asemiconductor device is disclosed that maximizes the adhesion propertyof a chemical enhancer on the surface of a diffusion barrier layer andthus improves the filling property of copper, by performing a plasmaprocess after the chemical enhancer is deposited while a copper metalwiring is formed by means of a chemically enhanced chemical vapordeposition (CECVD) method. The invention will be described in detail byway of a preferred embodiment with reference to accompanying drawings.

[0011] As shown in FIG. 1A, an interlayer insulating film 12 is formedon a substrate 11 in which an underlying structure is formed. Then, theinterlayer insulating film 12 is patterned by a single damascene or adual damascene process to form a damascene pattern consisting of acontact A and a trench B. After that, a cleaning process is performed.At this time, the interlayer insulating film 12 is formed by depositinginsulating materials having a low dielectric constant. The cleaningprocess is performed using RF plasma when the bottom layer is a metallayer such as tungsten, aluminum, and a suitable like metal, and isperformed using a reactive cleaning method when the bottom layer is ametal layer made of copper.

[0012] As shown in FIG. 1B, after a diffusion barrier layer 13 is formedon the entire structure in which the damascene pattern is formed, aplasma process is performed.

[0013] The diffusion barrier layer 13 is formed by one of the following:depositing titanium nitride (TiN) by a method that includes ionized PVD,CVD and MOCVD methods, tantalum (Ta) or tantalum nitride (TaN) byionized PVD method or CVD method, tungsten nitride (WN) by CVD method,and a titanium compound including aluminum nitride (TiAlN), titaniumsilicon nitride (TiSiN) and tantalum silicon nitride (TaSiN) by PVD orCVD method.

[0014] The plasma process performed after the diffusion barrier layer 13is formed serves to maximize the adhesion effect of a chemical enhancerdeposited by a subsequent process, which is either a remote plasmamethod or plasma etch method. In the remote plasma method, reactivetreatment is employed to increase adhesion sites of the chemicalenhancer. In the plasma etch method, single or dual frequency etch ispossible. The plasma process may be performed using a single gas thatincludes hydrogen, argon, and nitrogen, or using a gas mixture ofhydrogen and argon. The plasma process may be performed in a single stepor may be performed in multiple steps of between 1 and about 10 steps.

[0015] The supply power used for the plasma process ranges from about 50W to about 10 kW, and the process time ranges from about 1 second toabout 10 minutes. Also, in case of performing the plasma process using asingle gas such as hydrogen, nitrogen, argon and helium, the flow rateof each of the single gases ranges from about 50 standard cubiccentimeter per minute (sccm) to about 500 sccm. In the mixture gas, thehydrogen content ranges from about 5% to about 95% and the argon contentranges from about 5% to about 95%.

[0016] Meanwhile, when using the single step, either a single gas or amixture of the single gases may be used. In the multiple step process,after the single gas of argon or the mixture gas is first used, theprocess using hydrogen gas is repeated from 1 to about 10 times.

[0017] During the plasma process, within the chamber containing ashowerhead and substrate, the temperature of the substrate is keptbetween about 10° C. and about 350° C.; the distance between substrateand shower head is between about 5 mm and about 50 mm and the pressurewithin the chamber ranges from about 0.3 Torr to about 10 Torr.

[0018] As shown in FIG. 1C, a chemical pre-process using a catalyst,which is a chemical enhancer, is performed on the diffusion barrierlayer 13, which underwent the plasma process as discussed above. At thistime, the chemical enhancer may use an iodine-containing liquidcompound, which includes: Hhfac:H₂O (1:2), Hhfac and TMVS(trimethylvinylsilane), pure iodine, iodine-containing gas,iodine-containing water vapor, and liquid and gas state of group VIIelements, e.g., F, Cl, Br, I, and At, and liquid and gas states ofcompounds thereof, wherein the process time is from about 1 second toabout 10 minutes. Also, the catalyst process temperature ranges fromabout −20° C. to about 300° C.

[0019] As shown in FIG. 1D, a copper metal wiring 14 is formed on theentire structure so that the damascene pattern can be filled.

[0020] The filling with copper may be formed by use of all kinds ofcopper precursors using hfac such as, for example, Cu(hfac)VTMOS series,Cu(hfac)DMB series, and copper hexafluoroacetylacetonatetrimethylvinylsilane (Cu(hfac)TMVS) series, and is deposited by means ofMOCVD method using all the deposition equipments on which a liquiddelivery system (LDS) such as a direct liquid injection (DLI), a controlevaporation mixer (CEM), an orifice, and a spray, are mounted. The flowrate of the copper precursor ranges from about 0.1 sccm to about 5.0sccm.

[0021] Also, when the copper metal wiring is formed, a carrier gas thatincludes helium, hydrogen, and argon, is used at flow rates betweenabout 100 sccm and about 700 sccm. The pressure within the reactivechamber ranges from about 0.5 Torr to about 5 Torr, and the temperaturewithin the reactive chamber is kept about the same as that of thedeposition equipment, and the temperature of the shower head iscontrolled to be constant.

[0022] Further, the deposition temperature of copper ranges from about50° C. to about 300° C. and the distance between the shower head and thesusceptor plate within the reactive chamber is maintained between about5 mm and about 50 mm.

[0023] After copper is filled by the above method, a thermal process isperformed under hydrogen reduction atmosphere at a temperature fromabout room temperature to about 450° C. for about 1 minute to about 3hours, so that the shape of grain texture can be changed. The hydrogenreduction atmosphere at this time may use H₂ or a hydrogen mixture gasin which Ar comprises from about 0 to about 95% or N₂ is mixed into H₂.

[0024] As shown in FIG. 1E, chemical mechanical polish (CMP) process isperformed so that the copper metal wiring 14 is maintained at thedamascene pattern, thus exposing the surface of the interlayerinsulating film 13. Then a cleaning process is performed.

[0025] An illustration of the present invention has been described withreference to a particular application. Those having ordinary skill inthe art and access to the teachings of the present invention willrecognize additional modifications and applications within the scopethereof.

[0026] Therefore, the appended claims are intended to cover any and allsuch applications, modifications, and embodiments within the scope ofthe teachings of the present invention.

What is claimed are:
 1. A method of manufacturing a copper metal wiringin a semiconductor device, comprising the step of: forming an interlayerinsulating film on a substrate in which an underlying structure isformed; forming a damascene pattern; performing a cleaning process;forming a diffusion barrier layer on entire structure in which thedamascene pattern is formed; performing a plasma process for the entirestructure in which the diffusion barrier layer is formed; performing achemical pre-process using a chemical enhancer for the diffusion barrierlayer for which the plasma process is performed; depositing copper onthe entire structure so that the damascene pattern can be filled; andperforming a chemical mechanical polish process so that the damascenepattern can be filled, thus forming a copper metal wiring only withinthe damascene pattern.
 2. The method of manufacturing a copper metalwiring in a semiconductor device according to claim 1 , wherein theunderlying structure comprises a bottom layer comprising a metal layerselected from the group consisting of tungsten and aluminum, and thecleaning process comprises use of a RF plasma.
 3. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the underlying structure comprises a bottom layercomprising copper and the cleaning process comprises a reactive cleaningmethod.
 4. The method of manufacturing a copper metal wiring in asemiconductor device according to claim 1 , wherein the step of formingthe diffusion barrier layer is selected from the group consisting of:depositing titanium nitride by a method selected from the groupconsisting of ionized PVD, CVD and MOCVD methods; depositing tantalum ortantalum nitride by the ionized PVD or the CVD method; depositingtungsten nitride by the CVD method; and depositing a compound selectedfrom the group consisting of aluminum nitride, titanium silicon nitrideand tantalum silicon nitride by the PVD or the CVD method.
 5. The methodof manufacturing a copper metal wiring in a semiconductor deviceaccording to claim 1 , wherein the step of performing the plasma processuses a remote plasma method or a plasma etch method.
 6. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the step of performing the plasma process uses asingle gas selected from the group consisting of hydrogen, argon,nitrogen and helium.
 7. The method of manufacturing a copper metalwiring in a semiconductor device according to claim 6 , wherein the stepof performing the plasma process comprises delivering the single gas ata the flow rate from about 50 sccm to about 500 sccm.
 8. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the step of performing the plasma process uses agas mixture comprising hydrogen and argon.
 9. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 8 , wherein the gas mixture comprises from about 5% to about95% hydrogen and from about 5% to about 95% argon.
 10. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the step of performing the plasma process isperformed in a single step or in multiple steps comprising from 1 toabout 10 steps.
 11. The method of manufacturing a copper metal wiring ina semiconductor device according to claim 1 , wherein the step ofperforming the plasma process comprises using a power supply rangingfrom about 50 W to about 10 kW and the process time ranges from about 1second to about 10 minutes.
 12. The method of manufacturing a coppermetal wiring in a semiconductor device according to claim 1 , whereinthe plasma process is performed in a single step and utilizes a mixtureof gases.
 13. The method of manufacturing a copper metal wiring in asemiconductor device according to claim 1 , wherein the step ofperforming the plasma process is performed in multiple steps comprisinga first step utilizing a single gas of argon or a mixture of gases, anda subsequent step using hydrogen gas that is repeated from about 1 toabout 10 times.
 14. The method of manufacturing a copper metal wiring ina semiconductor device according to claim 1 , wherein the plasma processis carried out in a chamber comprising a showerhead and the plasmaprocess comprises: maintaining a temperature of the substrate betweenabout 10° C. and about 350° C.; maintaining a distance between thesubstrate and the showerhead between about 5 mm about 50 mm; andmaintaining a pressure within the chamber that houses the substratebetween about 0.3 Torr and about 10 Torr.
 15. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the chemical enhancer comprises one selected fromthe group consisting of: an iodine-containing liquid compound, Hhfac:H₂O(1:2), Hhfac and trimethylvinylsilane (TMVS), an iodine-containing gas,an iodine-containing water vapor, and a compound comprising at least onegroup VII element.
 16. The method of manufacturing a copper metal wiringin a semiconductor device according to claim 1 , wherein the chemicalpreprocess is performed for a time period ranging from about 1 second toabout 10 minutes.
 17. The method of manufacturing a copper metal wiringin a semiconductor device according to claim 1 , wherein the chemicalpreprocess is performed at a temperature ranging from about −20° C. toabout 300° C.
 18. The method of manufacturing a copper metal wiring in asemiconductor device according to claim 1 , wherein the copperdepositing step comprises the use of copper precursors with hfacselected from the group consisting of Cu(hfac)VTMOS series, Cu(hfac)DMBseries, and copper hexafluoroacetylacetonate trimethylvinylsilane(Cu(hfac)TMVS) series.
 19. The method of manufacturing a copper metalwiring in a semiconductor device according to claim 1 , wherein thecopper depositing step comprises the use of a copper precursor having aflow rate ranging from about 0.1 sccm to about 5.0 sccm.
 20. The methodof manufacturing a copper metal wiring in a semiconductor deviceaccording to claim 1 , wherein the copper depositing step comprisesdelivering carrier gases selected from the group consisting of helium,hydrogen, and argon at a flow rate ranging from about 100 sccm to about700 sccm.
 21. The method of manufacturing a copper metal wiring in asemiconductor device according to claim 1 , wherein the copperdepositing step comprises maintaining a pressure within a reactivechamber ranging from about 0.5 Torr to about 5 Torr.
 22. The method ofmanufacturing a copper metal wiring in a semiconductor device accordingto claim 1 , wherein the copper depositing step comprises maintaining atemperature of the device between about 50° C. and about 300° C.
 23. Themethod of manufacturing a copper metal wiring in a semiconductor deviceaccording to claim 1 , wherein the copper depositing step is carried outin a reaction chamber and comprises maintaining a distance between ashower head and a susceptor plate within the reaction chamber betweenabout 5 mm and about 50 mm.
 24. The method of manufacturing a coppermetal wiring in a semiconductor device according to claim 1 , whereinthe copper depositing step comprises performing a thermal process undera hydrogen reduction atmosphere at a temperature ranging from about roomtemperature to about 450° C. for a time period ranging from about 1minute to about 3 hours.
 25. The method of manufacturing a copper metalwiring in a semiconductor device according to claim 24 , wherein thecopper depositing step comprises utilizing hydrogen or a gas mixturecomprising hydrogen argon and nitrogen, or a gas mixture comprisinghydrogen and nitrogen.